I am making a website that requires a basic slideshow that can be easily updated. Is there a free and easy way to do this, i.e. a code? Or to update do i need to take the site down and "re-host" it again?
First, get your slide show up and running on your local machine. There are tons of slideshows available on the Internet, for example: http://lokeshdhakar.com/projects/lightbox2/
Learn how to get the slideshow running on your machine, then learn to make a few edits on it... just on your local machine first.
This will be the exact same procedure you'll use to update it in the future... except that you will then upload the new version to you web server via an FTP program. http://filezilla-project.org/
This FTP program is how you will interface with the server. You will not be taking anything down, you will just be updating existing files already on the site.
Eye for Video